Leg extension



FIG. 1 is a front, right side and top perspective view of a leg extension showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side elevational view thereof; and,

FIG. 5 is a right side elevational view thereof.

The appearance of the leg extension from the underside is not part of the claimed design.

The broken lines illustrate environmental portions of the leg extension and form no part of the claimed design. 

The ornamental design for a leg extension, as shown and described. 